Percentage Increase and Decrease Formula (Easy Examples)
Percentage change tells you how much something has grown or shrunk compared to where it started. Businesses use it for sales growth, price hikes, expense changes and salary revisions. Use our percentage calculator to check your answer, or follow the steps below.
The formula
Percentage change = (new value − old value) ÷ old value × 100
- If the result is positive, it is a percentage increase.
- If the result is negative, it is a percentage decrease.
Percentage increase example
Your rent went from ₹20,000 to ₹23,000.
- Difference = 23,000 − 20,000 = 3,000
- 3,000 ÷ 20,000 = 0.15
- 0.15 × 100 = 15% increase
Percentage decrease example
A supplier lowered the price of a part from ₹500 to ₹425.
- Difference = 425 − 500 = −75
- −75 ÷ 500 = −0.15
- −0.15 × 100 = 15% decrease
How to increase or decrease a number by a percentage
- Increase by 12%: multiply by 1.12. ₹5,000 becomes ₹5,600.
- Decrease by 12%: multiply by 0.88. ₹5,000 becomes ₹4,400.
Why a 50% rise and a 50% fall do not cancel out
₹100 rising by 50% becomes ₹150. Falling by 50% from ₹150 gives ₹75, not ₹100. To get back from ₹150 to ₹100 you need a 33.3% fall. The base changes each time, so always divide by the starting value.
Where businesses use it
- Sales growth: compare this month with last month, or this year with last year.
- Price revision: work out how much to increase your rates. Add the new rate to your quotation.
- Cost control: track which expense is rising fastest.
- Salary hike: new salary = old salary × (1 + hike % ÷ 100).
FAQs
What if the old value is zero?
The percentage change cannot be calculated, because you cannot divide by zero. Describe it as "new" instead.
Is percentage difference the same as percentage change?
Not exactly. Percentage change uses the old value as the base. Percentage difference compares two values without a "before" and "after", using their average as the base.
New to percentages? Start with how to calculate percentage.